ruby on rails - Difference between flash.now and @instance_var -

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i'm wondering difference between using flash.now , using instance variable (e.g. @error_message)?

on related note, how flash work when have multiple servers running, , there's probability subsequent request executed different server?

i'm wondering difference between using flash.now , using instance variable (e.g. @error_message)?

effectively not difference since both values gone after request completes. think it's more of convenience view code can check 1 place error messages instead of having check both flash , instance variable.

on related note, how flash work when have multiple servers running, , there's probability subsequent request executed different server?

the flash lives in session, typically persisted database. if have multiple instances of rails app running , using same database, have shared access flash object. it's therefore not problem @ if server writes flash object , server b reads out on next request.


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